CHICAGO — Jason Hammel isn't going to apologize for pitching aggressively. That's what's made him a pitcher the Orioles have learned to count on to give them a chance to win every time out.

Make no mistake, the fact that Hammel — who allowed two home runs in the Orioles' 5-2 loss to the Chicago White Sox Tuesday night at U.S. Cellular Field — has allowed 10 homers in his past six starts troubles the veteran right-hander.

But looking back on his outing Tuesday, it was what happened before Adam Dunn's two-run seventh inning homer that had Hammel most frustrated.

Hammel had allowed just two runs over his first six innings of work before an 0-2 curveball to Alejandro De Aza bounced in the dirt and hit De Aza in the shin.

Two batters later, De Aza would score the eventual winning run, and then Dunn jumped on a 2-2 hanging two-seamer for his 22nd homer of the season, giving the White Sox a 5-1 lead.

“I'm more frustrated by the hit by pitches than the home runs,” Hammel said. “I'm not going to shy away from pitching to a guy, but tonight I had two strikes on the hitter before with nobody on and it sets up and inning where trouble can happen. If I execute a curveball there where I want to instead of spiking it in the dirt and it hits him in the shin, it's a different story.”

The Orioles arrived in Chicago riding the momentum of a three-game sweep of the New York Yankees at Camden Yards. Then they upgraded their starting rotation Tuesday afternoon, adding right-hander Scott Feldman from the Chicago Cubs in a trade that dispatched struggling pitchers Jake Arrieta and Pedro Strop to the Windy City.

But their loss Tuesday, combined the Boston Red Sox's 4-1 win over the San Diego Padres, dropped the Orioles (47-37) to 3 ½ games behind division-leading Boston in the American League East standings.

After allowing two homers Tuesday, Hammel has yielded 18 longballs — tied for second most in the American League — in 17 starts. As a team, the Orioles have allowed a majors-worst 115 homers.

“The home runs are killing me this year,” Hammel said. “That's the bottom line. … I don't know how to answer [why], just balls up in the zone that are getting hit out this year that weren't last year. That's just the way I'm going right now. Mistakes are being amplified.”

After opening the season 7-2, Hammel hasn't won since May 27 — a span of six starts — and the Orioles have lost each of those games.

“I think the big thing when you look back at stuff like that, [is] how they got on base before they hit it,” Orioles manager Buck Showalter said. “Solos don't do much to you. It's what happens to set up those multiple runs.”

The Orioles managed six hits in seven innings against White Sox left-hander John Danks (2-5), who held the Orioles to two runs and struck out four and walked one.

“He's been around a while,” Orioles second baseman Brian Roberts said. “He knows how to pitch, and with guys on base he seems to get a little tougher. He used his changeup more, and he's got a good one. I think as much as anything he's good at disrupting your timing, mixing up hard and soft, and he did a good job of that tonight.”

Roberts' solo home run in the third inning put the Orioles up 1-0. Hitting from the right side, Roberts took a first-pitch delivery from Danks into the left-field seats. For Roberts, who was playing in his second game and first as second base since coming off the disabled list, it was his first homer in more than two seasons. His previous home run came on April 13, 2011.

Roberts also made a nice defensive play in his first game in the field since April 4, charging a ball hit by Alexei Ramirez that took a high hop over the mound, barehanding it on the run and throwing to first to nab the speedy Ramirez in the third inning.

“It's the extra things,” center fielder Adam Jones said of Roberts. “He's been working himself nonstop to get back at his position, and he misses the competitiveness, he misses this game. And it was a hell of a play. I'm just glad to see him back out there grinding and wanting to be out here.”

Hammel struck out five batters through his first three innings before Gordon Beckham's one-out single in the fourth tied the game 1-1, scoring Conor Gillaspie, who reached on a walk.

The White Sox (33-47), who entered the night off to their worst start after 79 games since 1998, took the lead in the sixth when Gillaspie hit a solo homer off Hammel, taking a hanging 1-0 pitch into the right-field seats. Chicago had lost five straight and 13 of its past 17 before Tuesday.

After Chicago's seventh-inning rally, the Orioles got a run back in the eighth on Jones' RBI single. But White Sox closer Addison Reed earned his 22nd save with a scoreless ninth, despite a two-out double from pinch hitter Nate McLouth.

Jake Arrieta, who was dealt to the Chicago Cubs today along with reliever Pedro Strop for pitcher Scott Feldman and catcher Steve Clevenger, was on his way to the Norfolk clubhouse to meet with some his teammates and say goodbye before packing and leaving for Triple-A Iowa, when he returned a...